[Bug] Switching to readonly mode with an empty editor

[Bezpro]

Describe a bug. If you switch the editor to read-only mode after initialization, an error appears: System.Exception: Cannot read property 'holder' of undefined

togglePreviewVisibility(visible: boolean) {
		this._editor.readOnly.toggle(visible); // this._editor.blocks.getBlocksCount() === 0
		this.previewVisible = visible;
	}

Editor.js version: 2.22.0

[aiavci]

Is there a workaround for this?

[seancheung]

Same as #1741